9 crayons cost $14.67. Which equation would help determine the cost of 11 crayons?
Answer: There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 9 crayons. We want to know the cost of 11 crayons. We can write the numbers of crayons as a proportion: $\dfrac{9}{11}$ We know 9 crayons costs $14.67. We can let $x$ represent the unknown cost of 11 crayons. The proportion of these costs can be expressed as: $\dfrac{\$14.67}{x}$ The cost changes along with the number of crayons purchased, and so the two proportions are equivalent. $\dfrac{9}{11} = \dfrac{\$14.67}{x}$